Spanish scientists successfully forced mature cells into an embryonic-like state inside the bodies of living mice, creating so-called reprogrammed induced pluripotent stem cells. Transforming mature cells into stem-like cells "means turning back the clock when everything in the environment favors the opposite," lead author Manuel Serrano said. The experiment, published in the journal Nature, opens the possibility that damaged tissue can be regenerated in patients with conditions such as diabetes and heart disorders.